1. Field of the Invention
The present invention relates generally to implantable medical devices, and more particularly, relates to implantable medical devices for the treatment of male impotence.
2. Description of the Prior Art
Implantable cylinders for the treatment of male impotence have been in use for some time. The more sophisticated of these devices employ fluid systems whereby the cylinder may be evacuated to produce the flaccid state and inflated to produce the erect state.
An early patent disclosing such an implantable system is U.S. Pat. No. 4,009,711, issued to Uson et al., which uses a pair of inflatable cylinders implanted in a corpus cavernosum of the penis. Each of the cylinders include a non-distensible portion of a semi-rigid material to be implanted into the root end of the corpus cavernosum and a pendulous, distensible body portion. The distensible body portion or inflatable cylinder is connected by tubing to a fluid reservoir located in the scrotal sac, and a check valve is provided to control the flow of fluid between the reservoir and the inflatable cylinder. A similar device is disclosed in U.S. Pat. No. 4,235,227, issued to Yamanaka.
A common problem of such early devices is adequate control of the pressurized sterile fluid and volumetric efficiency of the reservoir. U.S. Pat. No. 4,407,278, issued to Burton et al., addresses the control problem by providing the implantable cylinder with a check valve at the distal end. However, Burton et al., are not able to add volumetric efficiency. In fact the difficulty may be compounded by the use of a reservoir at the base of the penis, particularly with the embodiments using a separate pump located within the scrotum.